Detection of Crossed Cerebellar Diaschisis in Intractable Epilepsy Using Integrated 18 F-FDG PET/MR Imaging

Abstract Purpose Crossed cerebellar diaschisis involves reduced metabolism and blood flow in the cerebellar hemisphere contralateral to a supratentorial lesion. ASL is a valuable tool for quantifying regional cerebral blood flow. This study assesses ASL-MRI’s ability to detect CCD in epilepsy using integrated ¹⁸F-FDG PET/MRI and compares ASL with PET images in evaluating CCD. Methods 74 patients with drug-refractory epilepsy who underwent integrated ¹⁸F-FDG PET/MRI pre-surgery and CT/MRI post-surgery was analysed. Regions of interest were outlined on MRI images and simultaneously transferred to PET and ASL images. CCD detection was evaluated visually and semi-quantitatively using the absolute asymmetry index (AIabs). Results Out of 74 patients, PET detected CCD in 24 (32.43%) and ASL in 18 (24.32%), with no significant difference between them (P=0.274). Four CCD types were identified: both PET and ASL positive (16.22%), PET positive and ASL negative (16.22%), ASL positive and PET negative (8.10%), and both negative (59.46%). AIabs correlation was positive between PET and ASL in the epileptic zone (r=0.658, P<0.001) and cerebellum (r=0.407, P<0.001). In ASL CCD-positive cases, AIabs showed a negative correlation between the epileptic zone and cerebellum (r=-0.581, P=0.011), while in both PET and ASL CCD-positive cases, AIabs correlation was positive (r=0.670, P=0.017). Conclusion ASL is a viable method for assessing CCD in epilepsy patients. In CCD-positive cases, a notable discrepancy was observed: no correlation in PET images but a correlation in ASL images between the supratentorial epileptic zone and contralateral cerebellar hemisphere, indicating CCD might be linked to regional cerebral blood flow changes.